346 NATURAL HISTORY OF AFRICA. 



selves by leaving their accustomed shores, and hazarding 

 a journey across unknown oceans, have either been created 

 in more places than one, or have been enabled to transport 

 themselves by means different from any of those which are 

 now available in the ordinary course of nature.* 



If the natural means by which the more powerful species, 

 inhabiting the saline waters of the ocean, have spread 

 themselves from clime to clime, be in some measure within 

 the reach of our comprehension, it is otherwise with those 

 peculiar to rivers and the waters of inla.id lakes. How 

 these have contrived to migrate from one region to another, 

 and to people with identical species the depths of far-re- 

 moved and solitary waters, separated from each other by 

 chains of lofty mountains, or wide-extended wastes of desert 

 sand, is a problem which, in the present state of our 

 knowledge, we seek in vain to solve. f 



Of the genus Murctna several species occur in the African 

 seas. The spotted muraena (iW. guttata) was observed by 

 Forskall in the Red Sea. A small species of goby, scarcely 

 exceeding an inch in length, is found in the Nile. It is the 

 Gobius aphya of Linnaeus. We may here mention, that the 

 name aphya, by which this species has been distinguished, 

 seems to have been applied by the ancient writers to such 

 small fishes as they vaguely supposed to have been produced 

 rather from the foam of the ocean than according to the 

 usual process of nature.^ Several species of bull-head 

 ( Cottus) are described by Commerson, and the genus Scot 

 pcBna, so eccentric in its forms, is represented in the African 

 seas, among others, by the Cape scorpaena {S. Capensis), 

 mentioned by Gronovius. A magnificent fish, called the 

 opah dory {Zeus luna), inhabits the African shores. Dr. 

 Mortimer exhibited a fish of this kind to the Royal Society 

 in 1750, which was taken " on the coast of Leith ;" and he 

 adds (in the Phil. Trans, for that year), that the Prince of 

 Anamaboe, being then in England, immediately recognised 

 it, and said it was common in his country, and was excellent 

 eating. 



* See Gaymard's Mimoire sur la Distribution Geographique des 

 Poissons. 



t See further on this subject the 5th number of my Illustrations of 

 Zoology. 



t See Shaw's General Zoolog-j, vol. v. p 245 



